网页抓取数据并分析，特别包括分页数据的抓取。
包括8个按钮，每个按钮下的代码都可运行（第5、6个可能需要调试一下）。
有基本的页面抓取，不含分页数据的；
有含分页数据，且【下一页】的链接是网址的；
有含分页数据，且【下一页】的链接是__doPostBack；
有含分页数据，且【下一页】的属性是.gif，可通过F12找到href的。
参考网址：http://www.cnblogs.com/ceachy/articles/CSharp_Retrive_Page_Document.html
http://www.cnblogs.com/ghfsusan/archive/2010/05/26/1744820.html
using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System.IO;using System.Net;namespace WindowsFormsApplication1{ public partial class Form1 : Form { public Form1() { InitializeComponent(); } //private void button1_Click(object sender, EventArgs e) //{ // MessageBox.Show("hello world."); //} //WebBrowser web1 = new WebBrowser(); //web1.Navigate("http://www.xjflcp.com/ssc/"); //web.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(web_DocumentCompleted); //void web_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e) //{ // WebBrowser web = (WebBrowser)sender; // HtmlElementCollection ElementCollection = web.Document.GetElementsByTagName("Table"); // foreach (HtmlElement item in ElementCollection) // { // File.AppendAllText("Kaijiang_xj.txt", item.InnerText); // } //} //根据Url地址得到网页的html源码 private string GetWebContent(string Url) { string strResult=""; try { HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url); //声明一个HttpWebRequest请求 request.Timeout = 30000; //设置连接超时时间 request.Headers.Set("Pragma", "no-cache"); HttpWebResponse response = (HttpWebResponse)request.GetResponse(); Stream streamReceive = response.GetResponseStream(); Encoding encoding = Encoding.GetEncoding("GB2312"); StreamReader streamReader = new StreamReader(streamReceive, encoding); strResult = streamReader.ReadToEnd(); } catch { MessageBox.Show("出错"); } return strResult; } //为了使用HttpWebRequest和HttpWebResponse，需填名字空间引用 using System.Net; //以下是程序具体实现过程： private void button1_Click(object sender, EventArgs e) { //要抓取的URL地址 string Url = "http://list.mp3.baidu.com/topso/mp3topsong.html?id=1#top2"; //得到指定Url的源码 string strWebContent = GetWebContent(Url); richTextBox1.Text = strWebContent; //取出和数据有关的那段源码 int iBodyStart = strWebContent.IndexOf("<body", 0); int iStart = strWebContent.IndexOf("歌曲TOP500", iBodyStart); int iTableStart = strWebContent.IndexOf("<table", iStart); int iTableEnd = strWebContent.IndexOf("</table>", iTableStart); string strWeb = strWebContent.Substring(iTableStart, iTableEnd - iTableStart + 8); //生成HtmlDocument WebBrowser webb = new WebBrowser(); webb.Navigate("about:blank"); HtmlDocument htmldoc = webb.Document.OpenNew(true); htmldoc.Write(strWeb); HtmlElementCollection htmlTR = htmldoc.GetElementsByTagName("TR"); foreach (HtmlElement tr in htmlTR) { string strID = tr.GetElementsByTagName("TD")[0].InnerText; string strName = tr.GetElementsByTagName("TD")[1].InnerText; string strSinger = tr.GetElementsByTagName("TD")[1].InnerText; //插入DataTable strID = strID.Replace(".", ""); //AddLine(strID, strName, strSinger, "0"); //string strID = tr.GetElementsByTagName("TD")[0].InnerText; //string strName = SplitName(tr.GetElementsByTagName("TD")[1].InnerText, "MusicName"); //string strSinger = SplitName(tr.GetElementsByTagName("TD")[1].InnerText, "Singer"); ////插入DataTable //strID = strID.Replace(".", ""); //AddLine(strID, strName, strSinger, "0"); //string strID1 = tr.GetElementsByTagName("TD")[2].InnerText; //string strName1 = SplitName(tr.GetElementsByTagName("TD")[3].InnerText, "MusicName"); //string strSinger1 = SplitName(tr.GetElementsByTagName("TD")[3].InnerText, "Singer"); ////插入DataTable //strID1 = strID1.Replace(".", ""); //AddLine(strID1, strName1, strSinger1, "0"); //string strID2 = tr.GetElementsByTagName("TD")[4].InnerText; //string strName2 = SplitName(tr.GetElementsByTagName("TD")[5].InnerText, "MusicName"); //string strSinger2 = SplitName(tr.GetElementsByTagName("TD")[5].InnerText, "Singer"); ////插入DataTable //strID2 = strID2.Replace(".", ""); //AddLine(strID2, strName2, strSinger2, "0"); } //插入数据库 //InsertData(dt); //dataGridView1.DataSource = dt.DefaultView; } private void button2_Click(object sender, EventArgs e) { try { WebClient MyWebClient = new WebClient(); MyWebClient.Credentials = CredentialCache.DefaultCredentials;//获取或设置用于向Internet资源的请求进行身份验证的网络凭据 Byte[] pageData = MyWebClient.DownloadData("http://bbs.cup.edu.cn/cupbbs/ThreadList.aspx?fid=51"); //从指定网站下载数据 //string pageHtml = Encoding.Default.GetString(pageData); //如果获取网站页面采用的是GB2312，则使用这句 string pageHtml = Encoding.UTF8.GetString(pageData); //如果获取网站页面采用的是UTF-8，则使用这句 Console.WriteLine(pageHtml);//在控制台输入获取的内容 using (StreamWriter sw = new StreamWriter("C:\\Users\\yuan\\Desktop\\ouput.html"))//将获取的内容写入文本 { sw.Write(pageHtml); } Console.ReadLine(); //让控制台暂停,否则一闪而过了 } catch(WebException webEx) { Console.WriteLine(webEx.Message.ToString()); } } void web_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e) { WebBrowser web = (WebBrowser)sender; HtmlElementCollection ElementCollection = web.Document.GetElementsByTagName("Table"); foreach (HtmlElement item in ElementCollection) { File.AppendAllText("C:\\Users\\yuan\\Desktop\\ouputbutton3.txt", item.InnerText); } } private void button3_Click(object sender, EventArgs e) { WebBrowser web = new WebBrowser(); web.Navigate("http://www.chinahighway.gov.cn/html/staticHtml/front/index_lkcx.html"); web.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(web_DocumentCompleted); } private void button4_Click(object sender, EventArgs e) { string _StrResponse = ""; HttpWebRequest _WebRequest = (HttpWebRequest)WebRequest.Create("http://bbs.cup.edu.cn/cupbbs/ThreadList.aspx?fid=51"); _WebRequest.UserAgent = "MOZILLA/4.0 (COMPATIBLE; MSIE 7.0; WINDOWS NT 5.2; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)"; _WebRequest.Method = "Get"; WebResponse _WebResponse = _WebRequest.GetResponse(); StreamReader _ResponseStream = new StreamReader(_WebResponse.GetResponseStream(), System.Text.Encoding.GetEncoding("gb2312")); _StrResponse = _ResponseStream.ReadToEnd(); _WebResponse.Close(); _ResponseStream.Close(); File.AppendAllText("C:\\Users\\yuan\\Desktop\\ouputbutton4.txt", _StrResponse); } private void button5_Click(object sender, EventArgs e) { System.Net.WebClient WebClientObj = new System.Net.WebClient(); System.Collections.Specialized.NameValueCollection PostVars = new System.Collections.Specialized.NameValueCollection(); PostVars.Add("__VIEWSTATE", "dDwxNDMyMjQ3NTY4O3Q8O2w8aTwxPjs+O2w8dDw7bDxpPDM+O2k8Nz47PjtsPHQ8O2w8aTwwPjtpPDE+O2k8Mj47aTwzPjtpP........省略了，太长了......."); //PostVars.Add("__EVENTVALIDATION", "此处是您需要提前得到的信息"); PostVars.Add("__EVENTTARGET", "grdThreadList:_ctl27:_ctl3"); //PostVars.Add("__EVENTARGUMENT", ""); //string s = "23$74$56"; //string[] str=new string[5]; //str=s.Split('$'); WebClientObj.Headers.Add("ContentType", "application/x-www-form-urlencoded"); try { byte[] byte1 = WebClientObj.UploadValues("http://bbs.cup.edu.cn/cupbbs/ThreadList.aspx?fid=51", "POST", PostVars); string ResponseStr = Encoding.UTF8.GetString(byte1); //得到当前页面对应的html 文本字符串 //GetPostValue(ResponseStr);//得到当前页面对应的 __VIEWSTATE 等上面需要的信息，为抓取下一页面使用 //SaveMessage(ResponseStr);//保存自己关心的内容到数据库中 File.AppendAllText("C:\\Users\\yuan\\Desktop\\ouputbutton5.txt", ResponseStr); } catch (Exception ex) { Console.WriteLine(ex.Message); } } private static string current__viewstate="";//保存当前页面对应的 __VIEWSTATE 等上面需要的信息，为再次点击按钮（抓取下一页面）使用 private string GetPostValue(string ResponseStr) { //...... return "";//略//解析ResponseStr，得到__VIEWSTATE的值 } private void button6_Click(object sender, EventArgs e) { System.Net.WebClient WebClientObj = new System.Net.WebClient(); System.Collections.Specialized.NameValueCollection PostVars = new System.Collections.Specialized.NameValueCollection(); PostVars.Add("__VIEWSTATE", current__viewstate); ////PostVars.Add("__EVENTVALIDATION", "此处是您需要提前得到的信息"); PostVars.Add("__EVENTTARGET", "grdThreadList:_ctl27:_ctl3");//通过for,改变其值，ctl1,ctl2,ctl3.... ////PostVars.Add("__EVENTARGUMENT", ""); ////string s = "23$74$56"; ////string[] str=new string[5]; ////str=s.Split('$'); WebClientObj.Headers.Add("ContentType", "application/x-www-form-urlencoded"); try { byte[] byte1 = WebClientObj.UploadValues("http://www.chinahighway.gov.cn/html/staticHtml/front/index_lkcx.html", "POST", PostVars); string ResponseStr = Encoding.UTF8.GetString(byte1); //得到当前页面对应的html 文本字符串 current__viewstate=GetPostValue(ResponseStr);//得到当前页面对应的 __VIEWSTATE 等上面需要的信息，为抓取下一页面使用 //SaveMessage(ResponseStr);//保存自己关心的内容到数据库中 File.AppendAllText("C:\\Users\\yuan\\Desktop\\ouputbutton6.txt", ResponseStr); } catch (Exception ex) { Console.WriteLine(ex.Message); } } private void button7_Click(object sender, EventArgs e) { try { WebClient MyWebClient = new WebClient(); MyWebClient.Credentials = CredentialCache.DefaultCredentials;//获取或设置用于向Internet资源的请求进行身份验证的网络凭据 Byte[] pageData = MyWebClient.DownloadData("http://gb.cri.cn/42071/2013/03/05/3245s4038640_2.htm"); //从指定网站下载数据 string pageHtml = Encoding.Default.GetString(pageData); //如果获取网站页面采用的是GB2312，则使用这句 //string pageHtml = Encoding.UTF8.GetString(pageData); //如果获取网站页面采用的是UTF-8，则使用这句 Console.WriteLine(pageHtml);//在控制台输入获取的内容 using (StreamWriter sw = new StreamWriter("C:\\Users\\yuan\\Desktop\\ouput7.html"))//将获取的内容写入文本 { sw.Write(pageHtml); } Console.ReadLine(); //让控制台暂停,否则一闪而过了 } catch (WebException webEx) { Console.WriteLine(webEx.Message.ToString()); } } //对分页数据抓取，当网页上【下一页】的属性是.gif格式的时候，而且鼠标停在【下一页】上面，页面下面显示的网址不完整（网址太长，只能看到部分）， //可以通过在网页上点击右键【查看源文件】,或F12【脚本】，找到对应的href，即可得到网址。 private void button8_Click(object sender, EventArgs e) { try { WebClient MyWebClient = new WebClient(); MyWebClient.Credentials = CredentialCache.DefaultCredentials;//获取或设置用于向Internet资源的请求进行身份验证的网络凭据 Byte[] pageData = MyWebClient.DownloadData("http://www.chinahighway.gov.cn/roadInfo/queryRoadInfo.do?queryType=map&startDate=&cantonName=&cantonCode=&infoType=3&endDate=&startPlanDate=&_page_size=50&roadName=&mapList=-1&endRealDate=&roadCode=&provinceList=-1&endPlanDate=&startRealDate=&page=3"); //从指定网站下载数据 string pageHtml = Encoding.Default.GetString(pageData); //如果获取网站页面采用的是GB2312，则使用这句 //string pageHtml = Encoding.UTF8.GetString(pageData); //如果获取网站页面采用的是UTF-8，则使用这句 Console.WriteLine(pageHtml);//在控制台输入获取的内容 using (StreamWriter sw = new StreamWriter("C:\\Users\\yuan\\Desktop\\ouput8.txt"))//将获取的内容写入文本 { sw.Write(pageHtml); } Console.ReadLine(); //让控制台暂停,否则一闪而过了 } catch (WebException webEx) { Console.WriteLine(webEx.Message.ToString()); } } }}